usb: Enable new Windows USB backend by default

Based on a stable 1% experimental launch in M-85 new backend appears to
be stable. Enabling it by default so that it rolls out to all users as
part of M-87.

Bug: 637404
Change-Id: I57d996c1cef5c5c097561c9c23b9ae713825e4a0
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2436292
Commit-Queue: Reilly Grant <reillyg@chromium.org>
Commit-Queue: James Hollyer <jameshollyer@chromium.org>
Auto-Submit: Reilly Grant <reillyg@chromium.org>
Reviewed-by: James Hollyer <jameshollyer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#811437}

device/base/features.cc

@@ -8,10 +8,15 @@
 
 namespace device {
 
-#if defined(OS_MAC) || defined(OS_WIN)
+#if defined(OS_MAC)
 const base::Feature kNewUsbBackend{"NewUsbBackend",
                                    base::FEATURE_DISABLED_BY_DEFAULT};
-#endif  // defined(OS_MAC) || defined(OS_WIN)
+#endif  // defined(OS_MAC)
+
+#if defined(OS_WIN)
+const base::Feature kNewUsbBackend{"NewUsbBackend",
+                                   base::FEATURE_ENABLED_BY_DEFAULT};
+#endif  // defined(OS_WIN)
 
 #if defined(OS_WIN)
 const base::Feature kNewBLEWinImplementation{"NewBLEWinImplementation",